The head of a Virginia news station that had previously employed a news reporter who fatally shot and killed two journalists and wounded a third victim during a live television interview Wednesday defended his newsroom in the wake of the ghastly crime. 

"Every now and then one falls through the cracks," said WDBJ General Manager Jeff Marks Thursday in response to reports that killer Vester Lee Flanagan was a notably disgruntled employee who years earlier had threatened colleauges.

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Flanagan killed WDBJ news reporter Alison Flanagan 24, and cameraman Adam Ward, 27, early Wednesday morning as the pair carried out a live on air interview with Vicki Gardner, executive director of the Smith Mountain Lake Regional Chamber of Commerce.

Gardner is recovering from the attack.

Flanagan later shot and killed himself while under police pursuit, but not before faxing a so-called "manifesto" to ABC News blaming racism for his outrage.

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Flanagan had filed formal complaints about percieved racial comments allegedly made by his WDBJ colleagues during his time as a news reporter — from March 2012 to February 2013. Flanagan was fired after multiple warnings about his poor work performance and inability to work well with others.

"We are still at a loss to figure out what happened to him in those two-and-a-half years, but most of our time we are spending focused on results of his actions yesterday — the loss of Adam and Alison, and the bond with the community," said Marks.

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Behind Marks, rows of WDBJ news staff stood, some hand-in-hand, wearing maroon and teal ribbons in honor of Parker and Ward.

Marks said all complaints filed by Flanagan were investigated and dismissed due to lack of evidence. 

On the day Flanagan was fired, Marks said, the distraught news reporter handed the former news director a wooden cross along with a cryptic warning: "You'll need this."